Diagnostics and testing 4.0L (Discovery 3)

Contents: Inspection and verification ⇩ Table of signs of malfunction ⇩ DTC Index ⇩

Inspection and verification

1. Check the validity of the customer complaint. Keep in mind that the vehicle has a number of systems that communicate with the message center, giving the driver information that is useful in diagnosing faults.

2. Perform a visual inspection for obvious signs of mechanical or electrical damage.

3. If an obvious cause for the problem you identified or the customer described is found, resolve it before moving on to further action. (if possible).

4. Before referring to the Symptom Chart or DTC Index, read all DTCs using the approved diagnostic system or scan tool. Clear all DTCs after troubleshooting.

Table of signs of malfunction

NOTE: For a more complete troubleshooting chart, refer to Section 303-14 - Electronic Engine Controls in the service manual.

Sign of malfunction	Possible reason	Action
The engine crankshaft turns, flashes occur, but the engine does not start	EVAP purge valve Fuel system Spark plugs Ignition coil fault(s)	For purge valve tests, refer to the guided diagnostic routine on the approved diagnostic system. For fuel and ignition system tests, refer to the appropriate section in the workshop manual.
Difficulty starting when cold	Check the concentration of antifreeze in the cooling system Battery Crankshaft Position Sensor (CKP) Fuel system EVAP purge valve	Check the coolant condition. For battery information and CKP sensor and fuel system testing details, refer to the appropriate section in the workshop manual. For purge valve testing, refer to the guided diagnostic routine on the approved diagnostic system.
Difficulty starting when hot	Leak in the injector Fuel system Fuel temperature sensor Intake Air Temperature (IAT) Sensor Mass Air Flow (MAF) Sensor EVAP purge valve Ignition system	For injector and fuel system, fuel temperature sensor, IAT sensor, MAF sensor, and ignition system tests, refer to the appropriate section in the service manual. For purge valve tests, refer to the guided diagnostic routine on the approved diagnostic system.
Difficulty starting after hot soak (the car remains stationary for some time after the engine has reached operating temperature)	Leak in the injector Fuel system Fuel temperature sensor IAT sensor MAF sensor EVAP purge valve Ignition system	For injector and fuel system, fuel temperature sensor, IAT sensor, MAF sensor, and ignition system tests, refer to the appropriate section in the service manual. For purge valve tests, refer to the guided diagnostic routine on the approved diagnostic system.

DTC Index

NOTE: Generic scan tools may not be able to read the codes listed or may only be able to read 5-digit codes. Match the 5 digits from the scan tool with the first 5 digits of the listed 7-digit code to identify the fault. (the last 2 digits provide additional information readable by an approved diagnostic system).

NOTE: For a complete list of ECM DTCs, refer to Section 303-14 - Electronic Engine Controls in the service manual.

DTC	Description	Possible cause	Action
P040200	Excessive consumption registered in the exhaust gas recirculation system A	Exhaust Gas Recirculation (EGR) valve is not installed correctly or is not secured EGR pipe blockage EGR valve sticking EGR heat exchanger blockage EGR Valve Circuit(s) High Resistance EGR valve circuit(s): short to ground EGR valve electrical circuit(s): short to battery voltage EGR valve malfunction MAF sensor malfunction	Refer to the appropriate section in the service manual. Check the MAF sensor and electrical circuits. Refer to the electrical manual.
P040500	Exhaust Gas Recirculation Sensor A Circuit Low Voltage	Right EGR Valve Circuit(s) High Resistance EGR valve circuit(s): short to ground EGR valve malfunction	Refer to the electrical manual and check the EGR valve electrical circuit. Repair/replace as necessary.
P040600	Exhaust Gas Recirculation Sensor A Circuit High Voltage	EGR valve electrical circuit: short circuit to +battery EGR valve malfunction	Refer to the electrical manual and check the EGR valve electrical circuit. Repair/replace as necessary.
P040900	Exhaust Gas Recirculation Sensor Circuit A	Range/performance issues, short circuit in differential pressure sensor circuit EGR valve malfunction	Refer to the electrical manual and check the EGR valve sensor circuit. (DIFF PRESS). Repair/replace as necessary.
P044100	Fuel Evaporative Control System - Incorrect Purge Flow	Limited capacity/leak in the pipeline of the Fuel Vapor Control System (EVAP)coal adsorber purge valve Reducing the capacity of the adsorber ventilation duct Purge valve malfunction	Check the integrity of the charcoal adsorber pipe and vent. Refer to the relevant section in the service station manual.
P044200	Leak detected in fuel vapor control system (small leak)	The fuel filler cap is not installed correctly. Filler cap seal failure Leak in the fuel vapor control system (adsorber, pipelines, etc.) Leak in the fuel tank Malfunction of the DMTL valve	Please refer to the relevant section in the service station manual.
P044700	Open circuit in the electrical control circuit of the ventilation of the fuel vapor recovery system	EVAP DMTL Valve Circuit Short to Ground	Refer to the electrical manual and check the electrical circuit of the DMTL valve. Repair/replace as necessary. Refer to the relevant section in the service station manual.
P044800	Short circuit in the electrical circuit of the ventilation control of the fuel vapor control system	EVAP DMTL Valve Circuit Short to Battery Voltage	Refer to the electrical manual and check the electrical circuit of the DMTL valve. Repair/replace as necessary. Refer to the relevant section in the service station manual.
P045500	Leak detected in fuel vapor control system (large leak/no flow)	Fuel filler cap not installed Damage/missing fuel tank filler cap seal Leak in the fuel vapor control system (adsorber, pipelines, etc.) Leak in the fuel tank DMTL valve failure	Check the cap and seal of the fuel filler cap, check the adsorber, piping, etc. Check the fuel tank for leaks, etc. Refer to the corresponding section in the service station manual.
P045800	Low Voltage in Evaporative Emission Control Valve Circuit	Purge Valve Control Circuit Short to Ground Purge Valve Control Circuit High Resistance EVAP Canister Purge Valve Malfunction	Refer to the electrical manual and check the DMTL valve electrical circuit. Repair/replace as necessary. Refer to the appropriate section in the workshop manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P045900	High Voltage in Evaporative Emission Control Valve Circuit	Purge valve control circuit: short circuit to battery +	Refer to the electrical manual and check the DMTL valve electrical circuit. Repair/replace as necessary. Refer to the appropriate section in the workshop manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P240100	Low Voltage in Evaporative Emission Control Pump Control Circuit	In-Tank Leak Detection Pump (DMTL) Circuit(s): Short to Ground DMTL Pump Circuit(s): High Resistance	Refer to the electrical manual and check the wiring between the ECM and the DMTL pump. Repair if necessary.
P240200	High Voltage in Evaporative Emission Control Pump Control Circuit	In-Tank Leak Detection Pump (DMTL) Circuit(s): Short to Battery +	Refer to the electrical manual and check the wiring between the ECM and the DMTL pump. Repair if necessary.
P240429	Evaporative Emission Control System Leak Detection Pump Sensing Circuit Range/Performance Problems	Main Tank Leakage Monitoring System (DMTL) Reference Leak	Check the fuel vapor control system for proper operation and leaks. Check the DMTL pump and electrical circuits. Refer to the electrical manual. Perform a DMTl test. Refer to the appropriate section in the service manual.
P24042F	Evaporative Emission Control System Leak Detection Pump Sensing Circuit Range/Performance Problems	Erratic signal from the DMTL (Direct Tank Leak Detection System)	Check the DMTL pump and electrical circuits. Refer to the electrical equipment manual. Refer to the relevant section in the service station manual.
P240500	Low Voltage in Evaporative Emission Control Pump Sensing Circuit	In-Tank Leak Detection Pump (DMTL) Circuit Low Reference Voltage	Refer to the electrical manual and check the wiring between the ECM and the DMTL pump. Repair if necessary.
P240600	High Voltage in Evaporative Emission Control Pump Sensing Circuit	In-Tank Leak Detection Pump (DMTL) Circuit High Reference Voltage	Refer to the electrical manual and check the wiring between the ECM and the DMTL pump. Repair if necessary.
P240B00	Low voltage in the heating element circuit of the leak control pump in the fuel vapor recovery system	Low voltage in the electrical control circuit of the heating element of the tank leak monitoring system (DMTL)	Refer to the electrical manual and check the wiring between the ECM and the DMTL pump. Repair if necessary.
P240C00	High Voltage in Evaporative Emission Control Pump Heating Element Circuit	High voltage in the electrical control circuit of the heating element of the tank leak monitoring system (DMTL)	Refer to the electrical manual and check the wiring between the ECM and the DMTL pump. Repair if necessary.
P245000	Performance issues/vapor control system multi-way valve stuck open	In-Tank Leak Detection Pump (DMTL) Circuit Shorted, High Resistance DMTL Switch Valve Malfunction	Refer to the electrical manual and check the wiring between the ECM and the DMTL valve. Repair/replace as necessary. Refer to the appropriate section in the workshop manual.
P245100	Fuel vapor control system multi-way valve stuck closed	In-Tank Leak Detection Pump (DMTL) Circuit Shorted, High Resistance DMTL Switch Valve Malfunction	Refer to the electrical manual and check the wiring between the ECM and the DMTL valve. Repair/replace as necessary. Refer to the appropriate section in the workshop manual.